Atmospheric measuring techniques with balloons having venting system that vents gas with diminished balloon elasticity

ABSTRACT

An apparatus is described. The apparatus includes a balloon venting system. The balloon venting system includes a clamp. The clamp is to clamp to the balloon so as to bear a mechanical load away from an opening in the balloon. The balloon venting system includes a fluidic channel that is coupled to the opening in the balloon. The opening in the balloon is not located at the bottom of the balloon. The balloon venting system includes an electro-mechanical device that is mechanically coupled to a valve. The electro-mechanical device is to drive the valve to open the channel so that gas within the balloon escapes the balloon when the valve is open and to close the channel so that gas remains within the balloon when the valve is closed.

FIELD OF THE INVENTION

The field of invention pertains generally to lighter-than-air flight,and, more specifically, to a balloon venting system that vents gas withdiminished balloon elasticity.

BACKGROUND

Balloon technology has received renewed focus with the increasing needfor geographic and/or atmospheric data, the comparably lower cost oflighter-than-air-flight (as compared to other forms of flight), theavailability of low cost balloon materials and the availability ofinexpensive, high performance communication technologies and/or sensingtechnologies (e.g., imaging, temperature, pressure, etc.).

FIGURES

A better understanding of the present invention can be obtained from thefollowing detailed description in conjunction with the followingdrawings, in which:

FIGS. 1 a and 1 b shows a balloon venting approach;

FIGS. 2 a, 2 b and 2 c show an embodiment of a clamp that can be used toachieve the venting approach of FIGS. 1 a and 1 b;

FIGS. 3 a through 3 d show a method for manufacturing a venting system;

FIGS. 4 a and 4 b shows more detailed embodiments of the clamp of FIGS.2 a, 2 b and 2 c;

FIG. 5 shows a more detailed embodiment of a venting system;

FIG. 6 shows an embodiment of an electrical design for a venting system;

FIG. 7 shows a balloon system that adopts the venting approach of FIGS.1 a and 1 b;

FIG. 8 shows a sounding/flight profile of a balloon system that adoptsthe venting approach of FIGS. 1 a and 1 b;

FIGS. 9 a through 9 c depict balloon measurement gathering over asurface area.

DETAILED DESCRIPTION

A particularly cost effective ballooning approach involves elasticballoons such as balloons composed of one or more polymers (e.g.,rubber, latex, silicone, chloroprene, polyurethane, vinyl, etc.). Suchballoons are easily/cheaply manufactured yet remain sufficientlynon-porous to contain a balloon's lifting gas (e.g., helium) over a widerange of temperatures and atmospheric pressures. In particular, low costelastic balloons allows for mass manufacturing of such balloons, which,e.g., allows for the concurrent release of large numbers of suchballoons in a common/same timeframe and/or geographic region so thatlarge amounts of information can be collected over the common/sametimeframe and/or geographic region.

A challenge with an elastic balloon, however, is that the elasticity ofthe balloon's material degrades over 24-48 hours of flight (e.g., due totemperature cycling, ultra-violet (UV) and/or ozone induced degradationmechanism(s)). Elasticity is important in the case of a traditionalelastic balloon that vents gas from an opening at the bottom of theballoon (venting gas from a balloon will cause the balloon to descend,or, increase its pre-existing rate of descent). Here, an elasticballoon, when expanded with lifting gas, naturally desires to contractinward to its normal, non-expanded shape. In the traditional approachwhere the lifting gas is vented from an opening at the bottom of theballoon, the contraction acts to force the venting gas from the opening.That is, the balloon's inward compression “squeezes” the lifting gas outof the bottom of the balloon.

If balloon elasticity degrades, however, the balloon's inward,contractive force likewise dissipates. As such, the venting of gas fromthe bottom of the balloon becomes more and more difficult to effect.

A solution, as observed in FIGS. 1 a and 1 b , is to release the liftinggas from an opening (e.g., at the top or “apex”) of the balloon. If anopening exists at the apex of the balloon, the balloon will be able tovent lifting gas if balloon elasticity has dramatically degraded or doesnot even exist. That is, the lighter than air lifting gas simply risesout of the balloon from the opening at the balloon's apex. Thus, even ifthe balloon's elasticity degrades, by reliably controlling the openingat the balloon apex, controlled amounts of lifting gas can be preciselyvented from the balloon allowing for, e.g., tight altitude control overextended periods of flight (e.g., beyond 48 hours).

As observed in FIGS. 1 a and 1 b , an airtight seal is formed when avalve 101 is “closed” in the apex vent system (FIG. 1 a ), whereas, theopening of the valve 101 effectively creates an opening at the balloonapex which allows the balloon's lifting gas to escape/vent (FIG. 1 b ).

A challenge however is the integration of a mechanical venting system atthe balloon apex. Without an adequately precautioned design, the ventingsystem can easily cause tearing or other destruction of balloon materialat the balloon apex. Here, the relative thinness of the balloon materialand/or the repeated expansive/contractive gas pressures within theballoon contribute to the propensity of the opening in the balloon towiden.

FIGS. 2 a through 2 c shows different views of a clamp to be implementedat the valve interface between the balloon opening and the apex ventingsystem. As can be seen in FIGS. 2 a through 2 c, wider/internal 201 andnarrower/external circular 202 O-rings are compressed together to form aclamp that causes the balloon to bear the load of the venting apparatusand the balloon's own internal compressive/expansive forces along awider diameter D away from the balloon opening.

By bearing the load of the venting apparatus and the internalcompressive/expansive forces away from the balloon opening, tearing orshearing or other failure at the balloon opening is avoided. In essence,the balloon material at the actual opening experiences little/no load orforce from either the venting apparatus or the balloon's internal forceswhich substantially eliminates any propensity of the balloon opening tofurther enlarge.

FIGS. 3 a through 3 d depict a process for installing the abovedescribed clamping apparatus around the balloon opening, and then,mounting the venting apparatus to the clamping apparatus. As observed inFIG. 3 a , first, an inner, wider clamp component (hereinafter simply“clamp”) 310 with corresponding O-ring 301 is inserted into the balloonopening. The O-ring 301 of the inner clamp 310 is mounted to a base orsubstrate, hereinafter referred to as a platform 311. In the particularembodiment of FIGS. 3 a through 3 d , both the balloon opening and innerclamp O-ring 301 are circular with the radius of the O ring 301 beinglarger than the radius of the opening.

It is pertinent to point out that a circular O-ring best protectsagainst the tearing of a circular balloon opening, and, a circularballoon opening best protects against the tearing of an opening in aspherical balloon. That is, the symmetry between the shape of theballoon, the shape of the opening and shape of the clamp all helpminimize tearing forces at the balloon opening. Circular clampstructures and/or openings can also be successfully used for, e.g., ovalshaped balloons. Likewise, oval shaped clamps and balloon opening can beused with oval or even spherical shaped balloons.

Other embodiments may have balloon shapes other than spherical or oval(e.g., square, rectangular, triangular, etc.) and therefore may havecorrespondingly similar/symmetric shaped balloon openings (e.g., squareor rectangular for a square or rectangular balloon, triangular for atriangular balloon, etc.) and clamp structures (e.g., square orrectangular for a square or rectangular opening, triangular for atriangular opening, etc.). For ease of discussion the remainder of thediscussion will assume a spherical balloon and circular balloon openingand clamp structure.

With the balloon being composed of elastic material, the opening in theballoon is easily stretched wider to allow for the insertion of theinner clamp 310 inside the balloon. Once the inner clamp 310 is insertedinside the balloon and the balloon opening has relaxed to its normal,smaller sized opening, the radius of the inner clamp's O-ring 301 iscentered about the circumference of the balloon opening.

Then, as observed in FIGS. 3 b and 3 c , the external clamp component(hereinafter, simply “clamp”) 312 is placed on the external balloonsurface and its narrower O-ring 302 is fitted into the form of theO-ring 301 of the internal, wider clamp. Here, the radius of thenarrower, external O-ring 302 is larger than the radius of the balloonopening but smaller than the radius of the wider, internal O-ring 301 ofthe internal clamp so that the external O-ring 302 tightly “fits into”the form of the internal O-ring 301 thereby forming a clamp that clampsthe balloon material being the two O-rings 301, 302. In alternateembodiments the wider ring is external to the balloon and the narrowerring is internal to the balloon. For ease of discussion the remainder ofthe discussion assumes the narrower ring is external to the balloon andthe wider ring is internal to the balloon.

The sandwiching of the balloon material between the O-rings along anouter radius D away from the radius of the balloon opening provides forthe aforementioned shielding of the balloon opening from theloads/forces associated with the venting apparatus and/or the balloon'sinternal compressive/expansive forces.

As can be seen in FIGS. 2 c and 3 c , in the particular embodiment beingdiscussed, both of the O-rings 301, 302 have a circular cross section.The circular cross section allows a leading edge region of the balloonmaterial (the smallest radius of balloon material that (first) touchesthe narrower, external O-ring 302 to “wrap” around an arc of thecircular cross section of the external O-ring 302. Moving radially awayfrom the opening along the balloon material between the O-rings, theballoon material transitions to a trailing edge region that wraps aroundan arc of the circular cross section of the wider, internal clamp 301.

The wrapping action of the balloon material around both O-rings 301, 302as described above combined with the O-rings being tightly pressedagainst one another (one fits tightly into the other) secures a ring (oranulus) of balloon material against the O-rings 301, 302 which, in turn,as described above, effectively transfers all loads/forces experiencedby the balloon in the vicinity of its apex to this ring/anulus ofballoon material rather than along the balloon's opening. As can be seenin FIGS. 2 c and 3 c , the balloon material at the actual openingobserves little/no force and essentially “drapes” or “lufts” inside theleading edge of the narrower, external O-ring 302.

In an embodiment, both O-rings are made of dense, yetelastic/compressible material that can keeps itselasticity/compressibility at low temperatures (e.g., silicone, buna-N,polyurethane, fluorosilicone) so that the narrower, external O-ring 302will tightly fit inside the shape of the wider, internal O-ring 301 withthe balloon material between them. For instance, if the radius of thewider, internal O-ring 301 is R1 and the radius of the cross section ofthe wider, internal O-ring is r1, the inner edge of the wider, internalring will be a distance R1-r1 from the center of the balloon opening.Likewise, if the radius of the narrower, external O-ring 302 is R2 andthe radius of the cross section of the narrower, external O-ring is r2,the outer edge of the narrower, external ring will be R2+r2 from thecenter of the balloon opening. If R1 −r1=R2=r2 the outer edge of thenarrower O-ring will just touch the inner edge of the wider O-ring.Although this is suitable for various embodiments, in preferredembodiments R1-r1 is slightly less than R2-r2 which forces one or bothO-rings to deformably compress which further strengthens their clampingability to each other and the balloon material. The rings of otherembodiments can be shaped other than in a circle (e.g., spherical,square, rectangular, etc.).

With the narrower, external O-ring 302 being fitted into the form of thewider, internal O-ring 301, and with both O-rings being approximatelycentered about the opening in the balloon apex, as observed in FIG. 3 c, screws 313, 314 are inserted into preformed holes in the externalclamp platform 312 that also mate with preformed, threaded holes in theinternal clamp platform 311. When the screws are securelytightened/anchored into the inner clamp platform 311, the internal andexternal clamps are tightened against one another and securely hold theaforementioned outer ring/anulus material of the balloon.

Note that in various embodiments the respective platforms 311, 312 ofboth the internal and external clamps are annular in shape havingcircular holes in their respective centers. When the platforms 311, 312are mounted together these holes are vertically aligned which creates afluid path/opening 315 from the inside of the balloon to the outside ofthe balloon. Although not specifically shown one or both of theplatforms may have walls that the bolts extend through. The inner walls,when the platforms are tightly secured against one another, form anair-tight chamber between the platforms and the balloon opening.

As observed in FIG. 3 d , the venting apparatus 316 is then mounted tothe platform 312 of the external clamp. Here, screws (not shown) areinserted into preformed holes (not shown) in the venting apparatussubstrate/platform 317 that also mate with preformed, threaded holes(not shown) in the external clamp platform 312. When the screws aresecurely tightened/anchored into the platform 312 of the external clamp,the venting apparatus 316 is securely anchored to the overall assembly.

The respective platforms of both clamps and the venting apparatussubstrate have openings so that a fluid pathway is formed between theexternal environment and the inside of the balloon. A valve 318 coversthe opening in the venting apparatus substrate to “close” the fluidpathway. A gas-tight chamber is formed around the fluid pathway betweenthe clamp platforms 311, 312 so that no gas can escape from the balloonwhen the valve is closed (the sidewalls of the air-tight seal caninclude the inner edge of the external, narrower O-ring and/orfeatures/walls that extend from either or both clamp platforms to theother, facing clamp platform).

When the valve of the venting apparatus is in a closed position, asdescribed at length above, the gas-tight chamber formed between theclamp platforms experience the internal conditions of the balloon. Whenthe valve of the venting apparatus is open, however, gas inside theballoon is able to vent through the fluid pathway thereby reducing thelift of the balloon. Understanding the rate at which gas escapes fromthe balloon and setting the opening of the valve for a precise amount oftime allows for the tight/precise release of a specific amount of gasfrom the balloon. As such, the rate of descent following the opening andclosing of the aperture can be precisely controlled.

Although the above embodiments have described the wider clamp beinginside the balloon and the narrower clamp being external to the balloon,in various embodiments this arrangement can be switched. That is, thenarrower clamp can be inserted into the balloon and the wider clamp canbe press-fit over the shape of the inner, narrower clamp on the outsideof the balloon. Additionally, although the above embodiments havedescribed the venting apparatus substrate 317 being a separate elementthat is mounted to the external clamp platform 312, in variousembodiments these two features can be combined. That is, the narrower,external O-rings are formed on the bottom the apparatus substrate 317.

FIGS. 4 a and 4 b show a more detailed view of an embodiment of thewider, internal (FIG. 4 a ) and narrower, external (FIG. 4 b ). Asobserved in FIGS. 4 a and 4 b , both clamping platforms have innersidewalls which form the gas-tight chamber when the platforms arescrewed together. In essence, the wider, internal clamp platform can beviewed as a disc of some thickness having a groove formed in the facethat mates to the narrower, external clamp. The groove is shaped toaccept the O-ring of the narrower, external clamp.

FIG. 5 shows a more thorough depiction of (a cross section of) anembodiment of the apex venting system 500 including its valve mechanicsand electronic circuitry. Note that the embodiment of FIG. 5 shows thenarrower, external O-ring 512 being integrated with the bottom side ofthe venting system substrate 517. As observed in FIG. 5 , the ventingapparatus includes a stepper motor 520 that is mechanically coupled to amoveable valve 518 that covers the fluidic channel between the balloonopening and the substrate 517. Here, under nominal conditions when theballoon is rising or descending according to plan, the valve is in aclosed position (tightly covers the fluidic channel) to preserve theamount the gas within the balloon and keep the balloon at its plannedrate of ascent/descent.

However, if a change in the balloon's current state is desired (fromascending to descending, or, an increase to its current rate ofdescent), the stepper motor 520 is activated to open the valve 518. Thevalve is opened for a calculated amount of time that corresponds to therelease of a specific amount of gas within the balloon. Once the valvehas been opened for the calculated amount of time to release the desiredamount of gas from the balloon, the stepper motor is again activated toclose the valve. The balloon then descends according to the new, lesseramount of gas within the balloon.

As observed in FIG. 5 , the venting apparatus includes a flex hinge 521and a lever arm 522 that is mechanically coupled to each of the valveassembly 523, stepper motor 520 and flex hinge 521. Rotation of thestepper motor axle is translated into up/down movement of a push-rod 524that is mechanically coupled to an underside of the lever arm 522opposite the flex hinge 521. In a normal “relaxed” state, the push rod524 is in a withdrawn state and the torque of the flex hinge 521 rotateslevel arm in a clockwise direction which drives the valve over/into thefluid channel to tightly cover the fluid channel.

When the fluidic channel is desired to be open, a signal is sent to thestepper motor 520 which causes the stepper motor to rotate in a firstdirection which, in turn, causes the push-rod 524 to extend upward. Theupward extension of the push rod 524 overcomes the torque of the flexhinge 521 and causes the level arm 522 to rotate in a counter clockwisedirection. The counter clockwise rotation of the level-arm lifts thevalve thereby exposing the fluidic channel and allowing gas to escapefrom the balloon. The venting system remains in this state for thedesired amount of time. Once the valve has been opened for the desiredamount of time, another signal is sent to the stepper motor 520 to causesecond rotation of the stepper motor 520 that results in the push-rod524 being withdrawn so that the apparatus can return to its normal,relaxed state with the valve being closed over the aperture.

Alternate embodiments may choose to integrate the electro-mechanicalproperties and the valve into a single component, such as, a diaphragmcomposed of a material whose diameter, rigidness and/or other structuralcharacteristic is responsive to, e.g., an electric and/or magnetic fieldsuch that, in one state, a first electric and/or magnetic field isapplied (e.g., in terms of field intensity and/or field direction) tothe diaphragm material thereby causing the diaphragm material to hardenand/or expand to cover the vent opening (in which case the valve isclosed), whereas, in a second state, a second different electric and/ormagnetic field is applied (e.g., in terms of field intensity and/orfield direction) to the diaphragm material thereby causing it to drapeand/or contract and expose the vent opening (in which case the valve isopen). Examples of potential materials include metallized mylar,conductive Ultra-high-molecular-weight polyethylene UHMWPE, conductivepolyimide, flexible sheet magnetic material, diaphragm with embeddedcoils, piezoelectric membranes, graphene and shaped-memory-alloys.Embodiments for the valve can therefore be any kind ofelectro-mechanical valve apparatus.

Additionally, although embodiments above have stressed a mechanicalmechanism to adhere the venting system to the balloon, in otherapproaches the mechanical venting apparatus may be adhered to theballoon with an adhesive glue that bears the load of the ventingapparatus and the internal expansive/compressive forces of the balloonaway from the balloon opening. For example, a (continuous orintermittent) “ring” of adhesive glue may be applied around the balloonopening (and/or at the bottom of the venting apparatus substrate/PCboard) at a sufficiently larger radius than the radius of the balloonopening.

It is therefore pertinent to recognize that the teachings of the instantspecification with regard to adhering a venting system to a balloonhaving an opening are not limited solely to clamps (or to adhesiveglues), but, more generally, to adhesive elements (both a clamp and anadhesive glue can be considered an adhesive element). For the sake ofdescriptive ease, the instant application will continue to refer to aclamp as the adhesive element.

FIG. 6 shows a high level view of the design for the venting system'selectronic circuitry. In various embodiments, the components of theelectronic circuitry are mounted to a surface (e.g., top surface) of theventing system substrate. As observed in FIG. 6 , the venting system'selectronic circuitry includes batteries 601, a capacitor bank 602, atrickle circuit 603 coupled between the batteries 601 and the capacitorbank 602. As described in more detail immediately below, the batteries601 normally power the supply voltage rail 604 for a controller 605, thestepper motor 606 and a communication interface 607. However, underextreme low temperature conditions (e.g., approaching −70° C. or below),the capacitor bank 602 is relied upon partially or wholly to power thesupply voltage rail 604.

In an embodiment, the batteries 601 are composed of lithium irondisulfide to provide long term, extended use over a large temperaturerange (other possible battery types are lithium thionyl chloride andlithium—titanate). At extreme low temperature conditions (e.g.,approaching −70° or below), however, the batteries 601 cannot providethe instantaneous amount of current needed to drive the stepper motor605 and other electronic components 606, 607. As such, the electricalsystem also includes a bank of capacitors 602 to provide the currentneeded by the stepper motor 606 (and other components 606, 607) when thebatteries 601 are incapable of providing the current.

Here, the trickle circuit 603 charges the capacitors 602 from thebatteries 601 until a maximum/desired voltage is observed on thecapacitors 602. If action by the stepper motor 605 is desired and thetemperature is sufficiently low to question the ability of the batteries601 to drive the stepper motor, charge is drawn from the capacitors 602(instead of the batteries 601) to provide the stepper motor's current.

The trickle circuit 603 then replenishes the capacitors 602 from thebatteries 601. When the trickle circuit 603 observes the capacitors 602have again reached their maximum/desired voltage, charge is again drawnfrom the capacitor bank 602 to provide the stepper motor 605 current.The process then continues until the stepper motor 605 has advanced thedesired amount or the temperature has increased to a level at which thebatteries 601 can provide the stepper motor current. In an embodiment,the capacitor bank 602 stores enough charge to supply at least one stepof the stepper motor (and provide current for the controller 606 andcommunication interface 607). In this case, the trickle circuit 603continues to replenish the batteries in between one or more steppermotor steps (which depletes the capacitor charge).

In various embodiments the trickle circuit 603 employs a Maximum PowerPoint Tracking (MPPT) circuit 608 to track the batteries 601. Whencurrent is pulled from the batteries 601, the battery output voltagesags (increasingly so at lower temperature) and trying to charge thecapacitor bank 602 too quickly can collapse the battery voltage. Whenthe battery voltage sags below a set voltage, the MPPT circuit 608limits the trickle circuit's capacitor charge current to prevent thebattery voltage from sagging any further. Effectively, the MPPT circuit608 ensures the trickle circuit 603 charges the capacitors with as muchpower from the batteries 601 as the batteries 601 are able to give,which, in turn, causes the capacitor bank 602 to re-charge and thestepper motor to step as quickly as the on-board power supply permits.Here, program code executing on the controller 606 oversees theoperation of the MPPT circuit 608, trickle charge circuit 603 andcontrols to what extent the supply rail 604 is powered by the capacitorbank 602 and/or batteries 601.

Here, the controller 606 is coupled to a temperature sensing device(e.g., thermocouple, thermo-meter) and/or receives ambient temperatureinformation from its communication interface 607 so that the programcode executing on the controller 606 can keep track of the ambienttemperature and trigger reliance of the supply voltage from thebatteries 601 and/or capacitors 602. In other embodiments the tricklecharge 603 and MPPT circuits 608 operate with little or noinfluence/oversight by the controller 606 and instead determine when andto what extent the system should rely on the capacitor bank 602 forelectrical power.

In various embodiments the batteries 601 are composed of lightweight,low temperature batteries such as any of lithium iron disulfide, lithiumthionyl chloride and lithium-titanate. In same or other embodiments thecapacitor bank is composed of lightweight, low temperature, fastdischarge capacitors such as capacitors composed of any of Aluminumpolymer, Aluminum electrolytic, Tantalum polymer, Tantalum electrolytic,Ceramic, ELDC (“supercapacitors”), Mica, Niobium oxide, thin-film, etc.

FIG. 7 depicts an embodiment of a complete system with balloon 702, apexventing system 702 and payload 703. As observed in FIG. 7 , the payload703 is attached to the bottom of the balloon and primarily includesvarious sensors 704, a communication system 705, an avionics system 706,a ballast system 707 and a parachute system 708. A second controller 709is also integrated into the payload 703 to oversee/manage the operationof the payload systems 704-708 and the venting system 702.

In various embodiments the second controller 709 acts as a mastercontroller for the overall balloon and communicates not only with thevarious electronic sub-systems 704-708 of the payload electronics butalso with the controller of the apex venting system 702. The apexventing system controller receives communications and/or commands fromthe second (hereinafter, “master) controller 709 (e.g., temperaturereadings, commands to open the apex valve, commands to close the apexvalve, commands to open the apex valve for a certain amount of time,etc.) and executes lower level routines in response to thesecommunications (e.g., adjust battery charge rate, opens the apex ventvalve, etc.).

Communication between the master controller and the venting systemcontroller is accomplished through a communication link. As such, boththe venting system 702 and payload electronics 703 include some kind ofelectronic interface to communicate with one another. The type ofcommunication can be wireless (e.g., Bluetooth) or wired (e.g.,Universal Serial Bus (USB). In the case of the later wires can be runalong the side of the balloon between the venting system and the payloadelectronics to physically couple the two platforms.

The communication system 705 includes tele-communication circuitry(e.g., transmitter and receiver) for sending/receiving signals to/fromsatellite and/or ground based communication systems. In variousembodiments the payload's various sensors 704 are to sense data for theexternal measurements (including those far away from the balloon, e.g.,imagery taken with a camera on the balloon) the balloon has been sent tocollect (e.g., atmospheric measurements such as temperature (with anon-board thermometer), barometric pressure (with an on-board barometer),air content/quality (with an on-board gas detector, particle counter,etc.), wind velocity (from on-board GPS velocity), etc., or otherexternal measurements such as imagery (e.g., with on board camera andimage processor, etc.), GPS radio occultation measurements (withon-board GPS), synthetic aperture radar (with on-board radiotransceivers)) and balloon system data (e.g., temperature, ground speed(e.g., from multiple GPS position readings), altitude (with an on-boardaltimeter), GPS position (with an on-board GPS tracker), respectivestates of the various electronic sub-systems, etc.). Depending oncurrent flight state/circumstance, one or more items of any of this datacan be downloaded through a wireless down-link function of thecommunication system 705 for ultimate reception by, e.g., a ground basedmission control station. Likewise, one or more commands (e.g., to changeballoon altitude, to download certain data, to request balloon status,etc.) sent by the mission control station are received by the balloonthrough a wireless up-link function of the communication system 705.

The avionics system 706 includes flight related electronic circuitry forvarious “in-flight” functions such as altitude detection, globalpositioning system (GPS) implementation, ground speed determination,heading/bearing determination, etc.

The ballast system 707 includes a container filled with denseparticulate matter (e.g., sand) and a dispenser coupled to a motor. Whena determination is made to raise the balloon, increase the balloon'srate of ascent or decrease the balloon's rate of descent, the dispensermotor is engaged to open the container resulting in the release ofparticulate matter at a constant rate. The flow rate of the particulatematter combined with the length of time the container is openeddetermines the amount of total weight lost by the balloon, which, inturn, determines the rate at which the balloon will ascend in responseto the release of the particulate matter (release of particulate mattercan cause the balloon to transition from descending to ascending, or,cause the balloon to increase its rate of descent).

The parachute system 708 includes a parachute and release mechanics. Inthe event of free-fall (e.g., from balloon failure) or other loss ofbuoyancy situation the parachute can be released to prevent damage tothe balloon system from a hard landing.

In various embodiments, the electronic circuitry of the payload 703 ispowered by a second set of low temperature batteries (not shown), and, asecond capacitor bank (not shown) provides backup support for thepayload electronics at extreme low temperature environments. In variousembodiments, the storage capacity of the second capacitor bank isdesigned to provide current for, e.g., worst case peak power draws ofthe communication, avionic, dispenser motor and parachute releasemechanics.

The master controller 709 executes program code that adjusts the chargerate of the second capacitor bank in view of the ambient temperature andoutput of the second set of batteries. At extreme low temperatures whenthe batteries are deemed to be incapable of providing potential peakcurrent(s) drawn by the payload electronics 704-709, the mastercontroller 709 causes the payload electronics 704-709 to be sourced bythe capacitor bank in view of the state of the payload electronics704-709.

For example, if the communication system 705 is to execute an up-link ordown-link of information resulting in high current draw by thecommunication system 705, the controller will source the payloadelectronics or at least the communication system 705 by the payloadcapacitor bank. Thus, in various embodiments, the power delivery systembetween the payload batteries and the payload capacitor bank includes anetwork controlled by the master controller 709 to source certainspecific sub-systems that require high current draw from the capacitorsif the batteries are incapable of providing the same. The granularity ofthe network can vary from embodiment (e.g., each sub-system can beseparately powered by the batteries, or, only some or one of thesub-systems can be separately powered by the batteries). In still yetother embodiments no such network or ability to combine battery andcapacitor bank power exists and the payload electronics are sourcedeither by just the payload batteries or just the payload capacitor bank.

In other or combined embodiments, at low temperatures, the mastercontroller is able to place certain less critical electricalcircuitry/sub-systems into a low power, reduced-function state tominimize the worst case current draw from the payload capacitor bank atlow temperatures. In further embodiments, the master controller'sprogram code comprehends a priority hierarchy of the differentelectronic circuits/sub-systems and, e.g., gradually places lowestpriority circuits/systems into a low power, reduced function state asthe ambient temperature drops and/or the power output of the payloadbatteries declines (as temperature continues to drop, higher and higherprioritized systems in the hierarchy are placed into a low power,reduced function state).

As alluded to above, in various embodiments, a ground based “missioncontrol” station monitors balloon behavior, status and/or performanceand sends commands to the balloon to perform certain measurements,download/upload certain information, change its state from ascend todescend or vice versa and/or alter its rate of ascent or descent.

Here, the ground based mission control takes advantage of higherperformance computing systems to oversee and command the balloon'soverall experiment(s) and flight. By contrast, the balloon'scontroller(s) execute more simplistic, lower level, power efficientfunctions. For example, the ground based mission control system overseesand commands the balloon's overall flight pattern and communicatessimple commands to the balloon to effect the flight pattern (e.g.,“change rate of ascent to [X]”, “change rate of descent to [Y]”).

The controller(s) on the balloon execute the applicable mathematicalrelationships to convert the commands into the appropriate balloonactions (e.g., determining amount of time to open apex valve ordispenser). By performing the more complex overall experiment controland flight control on the ground and limiting the balloon's calculationsto the basic applicable physics and their corresponding limited actions,balloon battery/capacitor power is conserved.

As described at the onset of this description, the apex venting systemallows an elastic balloon to execute many more soundings during a singleflight than would be otherwise possible if the apex venting system didnot exist.

FIG. 8 shows an exemplary depiction of the type of flight profile thatis achievable with an elastic balloon having apex venting capability. Asobserved in FIG. 8 , the flight profile includes a large number ofascend-to-descend transitions and descend-to-ascend transitions. Asdiscussed above, in the case of a bottom venting elastic balloon, afterapproximately 48 hours of flight, the balloon's elasticity degrades tothe point where gas cannot be vented from the balloon below a fairlyhigh altitude (typically 15-20 km) resulting in loss of ability toinduce or control balloon descent at altitudes beneath the altitude.

Without the ability to freely induce or control balloon descent beneatha higher altitude after 48 hours of flight, repeated soundings over anumber of “cycles” between ascent/descent at any altitude—andparticularly with upper bounds at lower altitudes—is not possible after48 hours of balloon flight. Said another way, repeated cycles betweenascent and descent at any desired altitude range are only possiblewithin flight times of less than 48 hours.

By contrast, as observed in FIG. 8 , with the apex vent functionality,balloon flight time does not depend on balloon elasticity. As aconsequence, transition points from ascend to descend and descend toascend are easily adjustable over a wide altitude range over an extendedflight time beyond 48 hours, including, setting upper altitude bounds onsounding cycles at lower altitudes (such as altitudes 801 and 802)beyond 48 hours. The Applicant's apex venting elastic balloons can setupper sounding bounds (ascending to descending transitions) at altitudeswell beneath 15 km including upper sounding bounds at or beneath 10 kmsuch as 2 km or even sea level (0 km) after not only 48 hours of flightbut also 96 hours of flight. As such, after 48 hours of flight or after96 hours of flight, ascending to descending transitions can be set forany altitude beneath 15 km or even 10 km down to altitudes as low as 2km or even sea level.

As a consequence, the number of soundings at desired (especially lower)altitude levels/ranges can be greatly increased over a much longer totalflight time. Therefore, more meaningful experimentation/measurements canbe undertaken (e.g., GPS position vs. time, air temperature, humidity,atmospheric pressure) for longer flight times with an apex ventingelastic balloon that with a bottom venting elastic balloon.Significantly larger amounts of meaningful data can therefore becollected per balloon flight.

For example, if the balloon is sounded repeatedly for 60, 72, 84, 96 ormore hours between two (e.g., lower) altitude levels, highly “dense”measurement data can be taken between these altitude levels over anextended time period at lower cost as compared to a bottom ventingballoon (e.g., in the case of bottom venting balloon's, more than oneballoon would need to be released to capture the same amount of dataover the same time frame as a single apex venting balloon).

As highlighted above, with an apex venting elastic balloon, descent canbe induced at much lower altitudes over longer periods of time thanbottom venting balloons. As discussed above, in the case of bottomventing elastic balloons, degradation of balloon elasticity correspondsto higher and higher altitudes at which descent can be induced. Bycontrast, with apex venting, the ability to induce descent is not afunction of altitude and therefore can be induced at any altitudeincluding, e.g., after tens of hours of flight, much lower altitudesthan the altitude where a bottom vented balloon's descent can beinduced.

The ability to induce descent at lower altitudes translates into moredensely collected data in terms of time and altitude with an apex ventedballoon than with a bottom vented balloon. For example, if altitudes ofinterest are in a range from 5 km to 10 km, and after 20 hours of flightdescent can be induced with a bottom vented balloon only at altitudes of20 km or higher, after 20 hours of flight a bottom vented balloon canonly fly repeated soundings in a 5-20-5-20 km pattern. By contrast, anapex vented elastic balloon can be tightly controlled to fly repeatedsoundings precisely in the altitudes of interest: 5-10-5-10 km. Theformer (5-20-5-20) includes substantial time and air space wheremeasured data is of little value (the balloon is above 10 km). Bycontrast, with the later (5-10-5-10), the balloon is always collectingmeaningful data. Because more meaningful data can be collected with anapex vented elastic balloon than a bottom venting elastic balloon perflight, apex venting elastic balloons are believed to be a substantialimprovement in terms of cost per collected data set than bottom ventedballoons.

The ability to induce descent at lower altitudes additionally providesfor enlarged or extended sounding amplitudes over long periods of time.That is, the balloon is able to achieve repeated soundings where thealtitude difference between the descent-to-ascent transition and theascent-to-descent transition (and/or vice-versa) for one or moresoundings is 10 km or more. Thus, again, highly dense/meaningful datacan be collected over very precise altitude ranges over extended periodsof time.

Dense measurement collection per balloon can also be readilyextended/replicated to multiple, concurrently in-flight balloons so asto concurrently collect dense altitude profile measurement samplesacross large geographic areas. Here, again, the use of elastic balloonmaterials provides for reduced per balloon costs, which, in turn, allowsfor the manufacture and concurrent flight of multiple/many balloons.With many balloons concurrently in-flight, highly dense vertical andgeographic data can be captured so as to, e.g., better model orunderstand weather patterns over a range of altitudes across a largegeographic area.

FIGS. 9 a -9 c demonstrate a top down view of a group of balloons 901that are currently in-flight. Here, according to one approach, balloonsare concurrently released from the ground (e.g., all balloons arereleased within minutes of one another but could be within hours or evendays of one another), where, the release points for the balloons arestrategically separated with distances between balloons being above someminimal spacing (so as to cover a wider geographic area) but within somemaximum spacing (so as to increase the density of measurements over thegeographic surface area).

Over time the balloons will drift with the winds they are subjected to.FIGS. 9 a through 9 c depict a simplistic example in which all balloonsare subjected to the same winds at all times causing them to drift inunison (thereby preserving their release point organization). Thecollective drifting of the balloons effectively causes the surface areaover which measurements are taken to “scan” a volume of atmosphere abovethe earth's surface.

According to the approach of FIGS. 9 a through 9 c , initially, as shownin FIG. 9 a , a “line” of 100 balloons 901 spaced 10 km apart isreleased. Over time, as observed in FIG. 9 b , the balloons drift withthe wind at a rate, e.g., of 50 km/hr. After the balloons have beenadrift for 1 hour, as observed in FIG. 9 c , they will have traveled adistance of 50 km (1 hr×50 km/hr=50 km) and a second “line” of 100balloons 902 spaced 10 km apart is then released from the initialrelease points as the first line of balloons.

If the wind drift stays constant at 50 km/hr, the balloons willeffectively measure over a grid having spacings of 10 km (the balloonspacing) perpendicular to the wind direction and 50 km (the balloondrift distance in between balloon releases) along the wind direction.This grid then “scans” over the surface of the earth as the balloonsextend their flight in time. For example, if each of the balloon linesare in flight for 60 hours, the aforementioned grid will scan an area of1000 km×3000 km (=3×10⁶ km²) if each of the balloon lines are in flightfor 100 hours, the aforementioned grid will scan an area of 1000 km×5000km (=5×10⁶ km²) over the earth's surface. If third, fourth, etc. linesof balloons are released every hour, the density of the data collectedwithin the grid. That is, more readings are made over more time over thescanned surface area.

Moreover, as discussed at length above, during flight, each of theballoons are continually changing their altitude levels to effectivelycapture dense vertical/altitude profile data over the large surface area(e.g., their altitude levels repeatedly rise from 10 km to 20 km andthen fall from 20 km to 10 km). The result is cost effective yetextremely dense altitude profiling over large geographic areas over aconcise, in-flight time frame.

Such cost effective yet dense measurement taking over such largegeographic areas in such concise time frames is expected to greatlyenhance scientific understanding of weather and/or atmosphericconditions, which, in turn, can greatly enhance weather and/oratmospheric models (e.g., for hurricane/storm/tornado prediction and/ortracking; wind-turbulence prediction and/or tracking for commercialaviation, etc.). In general, the accuracy of such models depends uponthe density at which the measurements they are based on can be takenover time, geographic area and altitude. Release of large numbers ofinexpensive balloons for flight/drift over large regions of interestwith dense altitude profiling over concise time frames should be able togenerate the amount of data needed to achieve an improved level ofaccuracy above existing models.

Notably, in order to increase the measurement taking effectivenessand/or cost-effectiveness of the measurements, generally, atmosphericconditions change less above 20 km than between 10 km-20 km. As such,the planned frequency at which a balloon repeatedly rises and falls maybe much greater when the balloon is between 10 km-20 km than when theballoon is above 20 km. As such, for instance, a balloon's flight planmay schedule more soundings between 10 km-20 km than between 20 km-30 kmor between 10 km and 30 km (as could be the case with a bottom ventingballoon). Again, the ability to tightly control the sounding min and maxaltitudes can result in lower cost per collected data point as well astemporally finer data points. Apart from cost savings, the later can bemore valuable because, e.g., it leads to more precise modeling. As apoint of note, valuable data for storms tends to be below 10 km so theability to tightly control a max altitude of 10 km so that multiplesoundings can be performed that do not rise above 10 km (e.g.,5-10-5-10, etc.) should at least help improve storm modeling and/orreduce the costs needed to improve storm models.

Of course, in many scenarios, various ones of the balloons will besubjected to different winds thereby continuously distorting themeasurement grid arrangement that the balloons were originally releasedaccording to. In various embodiments, the data collected by a firstgroup of concurrently released balloons is used to establish a secondmeasurement grid arrangement for a second group of concurrently releasedballoons so as to, e.g., more effectively cover the geographic surfacearea of interest that both balloon groups approximately scan/cover. Forexample, after a first group of balloons are released, high wind regions(and direction(s) of such winds) may be identified by the first groupwhich, in turn, changes the release grid arrangement so that moreballoons will fly into these areas to enhance temporal data measurementthrough these areas (e.g., if strong south-easterly winds are expectedfor a group of balloon released in a certain area, a larger percentageof balloons are released along an area that extends along anorth-westerly direction from the area). Additional recursions (balloongroups) can be subsequently released with each subsequent group'srelease arrangement being better optimized for existing conditions basedon the total knowledge gained from all previously released groups.

Although embodiments above have emphasized that the venting system islocated at the apex of the balloon, other embodiments may mount orlocate the venting system in a location other than the absolute apex ofthe balloon. For example, some balloons may have a depression in thetop, center of the balloon and the venting system may nevertheless beplaced there. Other embodiments may also choose to place a ventingapparatus in a location other than the top, center of the balloon or theapex of the balloon. For example, a cigar shaped balloon may includefirst and second venting apparatus that are located towards the ends ofthe cigar rather than at the top, center apex of the cigar. In short,various embodiments for various reasons may choose to place the ventingapparatus away from the top, center of the balloon and/or away from theapex of the balloon. Generally, the venting system can be placedanywhere “above” or at least “next to” gas within the balloon so thatthe gas will naturally escape from the balloon when the valve is openwithout significant dependence on the balloon's elasticity (e.g., closerto a ceiling than a bottom of the balloon, somewhere in a top half ofthe balloon, etc.).

Although embodiments above have emphasized a balloon system that doesnot include a source of “lighter-than-air” gas (e.g., within the payloador otherwise) so that gas is added to the balloon only prior totake-off, other embodiments may choose to include a gas source, e.g., toextend flight lifetimes beyond those achievable with a balloon systemthat does not have a gas source.

Importantly, the approach of concurrently releasing multiple (e.g., tenor more) person-less balloons over a large geographic distances and/orareas and then taking measurements as the balloons drift (e.g., for atleast 1000 km or even 3000 km) and repeatedly ascend and descend duringtheir drift according to a designed altitude flight plan, as discussedat length above with respect to FIGS. 8 and 9 a,b,c, can be extended toballoons of any type and is not limited to elastic balloons and/orelastic balloons with apex venting capability. That is, as just oneexample, multiple person-less super pressure balloons (e.g., each withan on board lighter than air gas source) can be released en masse andtake measurements as they drift according to a designed altitude flightplan composed of soundings between specific altitude levels realizedwith repeated ascending-to-descending and descending-to-ascendingtransitions at certain altitudes.

Nevertheless, with data collection density being proportional to thenumber of balloons that are released, the cost of the overallmeasurement taking process is largely dependent on the cost of theballoon and its associated equipment/payload. As such, highly dense datameasurements collected over large geographic areas becomes morefeasible, from a cost perspective, as the balloons and their payloadsbecome less expensive. Notably, the cost of a balloon and its payloadgenerally declines with decreasing balloon and payload size and weight.The payload of a balloon is the total sum weight that is transported bythe balloon during flight other than the weight of the balloon materialitself (e.g., the combined weight of the venting apparatus, measuringequipment, electronics (power, communications, etc.) ballast, gaspumping apparatus (if any) all contribute to the balloon's payload).

Therefore, at least with the elastic apex venting balloon approachdescribed at length above, the Applicants have realized an affordablehigh data collection density technology. More specifically, theApplicant's balloon systems generally can be manufactured with 12 poundsof payload or less, or even 6 pounds of payload or less. As aconsequence, concurrent en masse release of balloons (e.g., at least tenballoons such as tens of balloons, hundreds of balloons, etc.) in anarrangement patterned over a large geographic distance and/or area isrealizable with the Applicant's technology. As described at lengthabove, the en masse release of balloons can be followed by repeatedascending-to-descending and descending-to-ascending transitionsaccording to a defined altitude flight plan (including altitudedifferences between ascending-to-descending transitions anddescending-to-ascending transitions (or vice-versa) of 10 km or greater)as they drift over 48 hours or more (or even 96 hours or more), e.g., sothat they drift at least 1000 km (or at least 3000 km), to effect manysoundings at specific altitudes and resulting high density datacollection over these altitudes.

Embodiments of the invention may include various processes as set forthabove. The processes may be embodied in program code ormachine-executable instructions. The instructions can be used to cause ageneral-purpose or special-purpose processor or controller to performcertain processes. Alternatively, these processes may be performed byspecific/custom hardware components that contain hard interconnectedlogic circuitry or programmable logic circuitry (e.g., fieldprogrammable gate array (FPGA), programmable logic device (PLD)) forperforming the processes, or by any combination of programmed computercomponents and custom hardware components.

Elements of the present invention may also be provided as amachine-readable medium for storing the program code ormachine-executable instructions. The machine-readable medium mayinclude, but is not limited to, floppy diskettes, optical disks,CD-ROMs, and magneto-optical disks, FLASH memory, ROMs, RAMs, EPROMs,EEPROMs, magnetic or optical cards, propagation media or other type ofmedia/machine-readable medium suitable for storing program code ormachine-executable instructions. For example, aspects of the presentinvention may be downloaded as a computer program which may betransferred from a remote computer (e.g., a server) to a requestingcomputer (e.g., a client) by way of data signals embodied in a carrierwave or other propagation medium via a communication link (e.g., a modemor network connection).

In particular, any/all of the balloon activities described, whetherwithin a single balloon assembly or amongst a group of balloons incollective flight, can be partially or wholly embodied as program code(e.g., firmware) that resides on the balloons and/or various forms ofhardware implementation (custom hardwired logic circuitry (e.g.,application specific integrated circuit (ASIC) logic circuitry),programmable logic circuitry (e.g., field programmable gate array (FPGA)logic circuitry), logic circuitry that executes program code (e.g., aprocessor or controller) or any combination. Various, e.g., oversightand/or control functions applied to one or more balloons can also beimplemented as any combination of program code executed on, e.g., a landbased computer (e.g., as application software) and/or any of thehardware possibilities described just above (e.g., in a land basedcomputer or “black box”).

In the foregoing specification, the invention has been described withreference to specific exemplary embodiments thereof. It will, however,be evident that various modifications and changes may be made theretowithout departing from the broader spirit and scope of the invention asset forth in the appended claims. The specification and drawings are,accordingly, to be regarded in an illustrative rather than a restrictivesense.

The invention claimed is:
 1. A method, comprising: releasing at leastten person-less, single balloon systems in a strategic arrangement tocover an area of interest, each of the single balloon systems comprisinga venting system comprising an opening in a balloon that is above gaswithin the balloon, on-board measuring equipment and an on-boardcontroller; drifting each of the single balloon systems for a distanceof at least 1000 km and for a duration of greater than 48 hours, andduring the drifting, controlling an altitude of each single balloonsystem in accordance with a corresponding altitude flight plan using thecorresponding on-board controller to control the venting system suchthat, after 48 hours of the drifting, each single balloon systemrepeatedly rises and falls and gas is repeatedly vented from the openingin the balloon of each single balloon system, wherein, the altitudeflight plan of each single balloon system includes, after 48 hours ofthe drifting, at least one altitude difference between ascent-to-descenttransition and descent-to-ascent transition of 10 km or more, and/or atleast one altitude difference between descent-to-ascent transition andascent-to-descent transition of 10 km or more, and wherein transitionpoints from ascent-to-descent and descent-to-ascent are adjustable bythe on-board controller during the drifting; taking measurements at eachof the single balloon systems using the corresponding on-board measuringequipment during the drifting, wherein, the measurements includeexternal and altitude measurements of the corresponding single balloonsystem; and, transmitting information resulting from the measurementsfrom the single balloon systems.
 2. The method of claim 1 wherein eachsingle balloon system's respective balloon is a latex balloon.
 3. Themethod of claim 1 wherein the duration of the drifting is at least 96hours.
 4. The method of claim 1 further comprising incorporating theinformation into an atmospheric model.
 5. The method of claim 1 wherein,as of the releasing, each of the single balloon systems carry no morethan 12 lbs of payload.
 6. The method of claim 5 wherein the duration ofthe drifting is at least 96 hours.
 7. The method of claim 1 wherein theexternal measurements are any of: temperature measurements; barometricpressure measurements; air content; air quality; wind velocity; and/or,imagery.
 8. The method of claim 1 further comprising each of the singleballoon systems using GPS equipment of the corresponding on-boardmeasuring equipment during the drifting.